This project is examining in vitro vascular responsiveness to catecholamine and non-catecholamine agonists and antagonists under a variety of conditions including altered ambient temperature, chemically-induced metabolic inhibition and alterations in hormone hemostasis with and without variations in tissue bath sodium content. Data derived from these studies will be examined to determine whether any of the above changes will induce adrenoceptor interconversions from beta to alpha and vice versa. Further, comparisons between experimental groups will determine whether interconversions that may develop do so because of direct effects of hormone variation or because of secondary effects such as salt retention or metabolic changes.